/*
 * Copyright 2024 LinQingYing. and contributors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * The use of this source code is governed by the Apache License 2.0,
 * which allows users to freely use, modify, and distribute the code,
 * provided they adhere to the terms of the license.
 *
 * The software is provided "as-is", and the authors are not responsible for
 * any damages or issues arising from its use.
 *
 */

package com.linqingying.cangjie.diagnostics.rendering

sealed class RenderingContext {

    abstract operator fun <T> get(key: Key<T>): T


    abstract class Key<out T>(val name: String) {
        abstract fun compute(objectsToRender: Collection<Any?>): T
    }

    object Empty : RenderingContext() {
        override fun <T> get(key: Key<T>): T {
            return key.compute(emptyList())
        }
    }
    class Impl(private val objectsToRender: Collection<Any?>) : RenderingContext() {
        private val data = linkedMapOf<Key<*>, Any?>()

        @Suppress("UNCHECKED_CAST")
        override fun <T> get(key: Key<T>): T {
            return data[key] as? T ?: key.compute(objectsToRender).also { data[key] = it }
        }
    }

    companion object {
        @JvmStatic
        fun of(vararg objectsToRender: Any?): RenderingContext {
            return Impl(objectsToRender.toList())
        }
    }
}
